For example, vacuum evaporation is used as a fabricating method of organic layers, such as an organic electro-luminescence (EL) device. Usually, in a vacuum evaporation method, a substrate is placed opposite to a film formation material under a vacuum environment, and the evaporated material obtained by heating a film formation material to vapor pressure temperature is made to adhere to the substrate surface. Here, a resistance heating method, a heater heating method, an induction heating method, an electron beam (hereinafter, referred to “EB”) method, etc. are cited as the heating method of the film formation material.
Among these, the resistance heating method performs energizing a container which contains the film formation material as a resistor, the heater heating method heats a container with the heater placed on the outer circumference of the container, and the induction heating method heats a container or a film formation material by an electromagnetic induction action from the induction coil installed outside. On the other hand, the EB method irradiates a film formation material with an electron beam from the exterior, and heats the film formation material.
By the way, since many organic materials have a low melting point and high vapor pressure, they evaporate at low temperature. Therefore, when using an organic material as the source of film formation of vacuum evaporation, heating temperature is set up low. For example, when forming the organic layer for an organic EL device, evaporating temperature is about 200 to 400 degrees C. Therefore, when evaporating an organic material, the vacuum evaporation rate in a low heating temperature range needs to be controlled.
However, in the case of a resistance heating method, since a container becomes a heating resistor, it is difficult to enlarge size of the container from the relation of electric capacity. In this method, although the heating rate is high, there is a problem that the loading weight of a film formation material is restricted and it is not suitable for the large-scale evaporation apparatus for mass production.
On the other hand, in the case of the heater heating method, since indirect heating of a container is performed, heating time is long and heating response is also not good and then it is difficult to control the vacuum evaporation rate. In particular, since the organic material has low thermal conductivity, the heating time may reach to several hours in a mass production apparatus. Furthermore, in this method, since a material inside the container is heated over the whole, the organic material remaining in the container to the last is exposed to the evaporating temperature for long duration, and there is a possibility of causing degradation, such as thermal decomposition.
In the case of EB method irradiation of a film formation material with an electron beam, the intermolecular bonding force of the organic material is weak (about several eV). Therefore, since intermolecular bonds are cut and molecules becomes high temperature if the organic material is directly irradiated with the electron beam of high energy, the problem of the organic material decomposition and deterioration occurs.
Accordingly, a technology which indirectly irradiates a container which contains organic material with an electron beam is proposed (for example, refer to Patent Document 1).
Furthermore, a technology which mixes the fine particles of an organic compound and a material with large thermal conductivity, such as ceramics, in a container is proposed as the way of improving thermal conductivity using the above-mentioned heater heating method (for example, refer to Patent Document 2). If composed in this way, ceramics etc. spread heat to the inside of the container, and the heating becomes uniform.
On the other hand, a technology which evaporates an organic material with an induction heating method is proposed (for example, refer to Patent Document 3). This technology discloses a method of charging the organic material into the container heated by electromagnetic induction, and performing electromagnetic induction heating of the container, or a method of charging the filler heated by electromagnetic induction with the organic material into the container, and performing electromagnetic induction heating of the filler. Since this method performs direct heating of the container, heating time is short compared with the above-mentioned indirect heating method, and the response of a vacuum evaporation rate is also excellent and control of the vacuum evaporation rate is easy.    Patent Document 1: Japanese Patent Application Laid-open No. H6-223970 (paragraph 0037)    Patent Document 2: Japanese Patent Application Laid-open No. 2001-323367 (paragraph 0014)    Patent Document 3: Domestic Re-publication of PCT International Publication for Patent Application No. 02/014575 (FIGS. 1 to 3)